System of electrical distribution.



W. H. COLE.

. SYST EM OF ELECTRICAL DISTRIBUTIOIIL APPLICATION FILED AUG. I2. 1915- RENEWED DEC. 8. I917.

1,27 6,331. Patented Aug. 20, 1918.

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a 5 H911 "fMIII- 'j W I I 5U Invenro'r." William C le z. .1 *Tfi w. H. COLE.

SYSTEM OF ELECTRICAL DISTRIBUTION.

APPLICATION FILED MIG. I2, I9I5- RENEWED DEC-8,1911- 1,276,331u' Patented M820, 1918.

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I, by; I! w 1,276,831. Patented Aug. 20,1918.

W. H. COLE.

SYSTEM OF ELECTRICAL DISTRLBVUTION. APPLICATION FlLED AUG-l2. 1915. RENEWED DEC. 8.1917.

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William Patented Aug. 20, 1918.

W. H-. COLE.

SYSTEM'OF ELECIRICAL ms md unou.

APPLICATION FILED AUG. I2, I915. RENEWED DEC-8' HI].

WILLIAM B. com, 01'? WALTHAM, massacnusmrs.

sYsTEm or ELECTRICAL iiIsTnIBUTIoN.

Application filed August 12, 1 915, Serial No. 45,238.

To all whom it may concern:

- Be it known that I, WILLIAM H. Conn, a

citizen of the United States, residing at -.tions. -In my -lVa1tham, 'county pf Middlesex, State of Massachusetts, have invented an Improvement in Systems of Electrical Distribution,

of which the following description, in connection with the accompanying drawing, is a specification,,like'characters on the draw in%representing like parts.

his invention relates to systems of electrical distribution and particularly to those systems whichijemploy a plurality of .con-

ductors arrangetl'in parallel and extending, between two receiving or distributing staisolat" when-,it-becomes' faulty. Y t

' isdesigned to become'operative to'disconneat a' conductor from thel'systefn when thevalue of the current carried b s'aid conduc tor differs from that of anot er conductor by a predetermined amount. This predetermined amount of normal unbalance is provided for by proper adjustment of the ie t lays and balancing transformers, and in actual practice,- therefore, said relays and bal ancing transformers are. adjusted so as to rmit the maximum amount ofnormal unhslancef'to occur witho'ut operating the disconnectingdevices, but to become operative to cause 1 k out which result in unbalanced currents greater than the amount occurringwhe'n no ultslare presentin the protected conductors,'-' The greater the amount of expected unbalance during. working conditions,- the coarser must-lie the setting a: the rela'y'and cient' will p a a us e'i'n giving pro tection.

In the usual lay-cutof anie'lectricaldis.

tributing system havin'gfpara'l'lel feeders,- it

ing capacity; 0 ers will vary mater ally due tofsuch causes frequently hap e'ns thatthei relative carrythe"parallel-connectedffeed as unequal length, ,difierence in' cross sec 'tion, difference in reactance, different tem- Specification of Letters ratcnt.

the system. I The object of my present invention is to patent No. 1,152,880, dated Septe 1nber 7, 1915,11 have illustrated and y describedan electrical-distributing system 0f type having means for automatically from the system ny conductorsconnection whenever faults oc- Patented Aug; 20, 1918. Renewed December a, 1011. Serial 110.208.3137.

parallel-connected conductors at points be tween the terminals thereof. It is, therefore, desirable to provide a construction which while capable of sensitive discrimination in the case of fault currents, is not responsive to the known or predeterminednormal unbalance or difference in current values which may exist during normal working of provide'means-to-be used in connection with two or more parallel-connected conductors sub ect to power flow in either direction and which may for one cause or another normally carry currents of values which vary in ratio with respect to the current'in one or m'or of the other'cpnductors in the same parallel-igroilmwhjch means will remain inoperativeso-long as said ra tio remains with- ,in predetermined limits, but which becomes y operative to out out and isolate any conduc- -The;device.of the aboye-rnehtioned patent a paratus embodying my present invention; t ere fore, it'is. possible to carry normally,

a greater or less current; in" one conductor than in another parallel conductor, and yet tween the maximum and g'ninimum current predetermined limit.

values" in the several conductors to exoeed a In the following description :1 current of a conductorhaving a reverse direction of flow.with respect to the currents in the other, [conductors is to be considered its/having a minimum value as compared with the maxi- I mum current in'the normal direction equal the coarser the relays are set the less efli to its-algebraic difference 'from said maximumcurrent;

" iI accomplish; the above objects by'employing one or more, relays associated with the conductors and which become -operative eds-wh t e arrent inoneof the ..c0uduc-, toast-is less than or exceeds the current in anotherconductor by a predetermined percentage. I

In order to give a proper understanding of the invention, I have illustrated herein some selected embodiments thereof which -to' out out a: faulted conductor whenever a fault develops which causes the ratio bewill now be described. it being understood that the invention is not limited to the construction shown.

Figure 1 is a partially dia rammatic view showing one embodiment 0 my invention;

Fi 2, 3, 4, 5 and 6 are similar views showing different embodiments of my invention;

Fig. 7 is a diagrammatic view showing my invention as applied to three'or more Darallel-connected conductors.

Referring first to Fig. 1 which shows a simple embodiment of t e invention, 1 and 2 designate the mains at two receiving or distributing stations, and these mai'ns'may be either in a ring, tandem or radial system of distribution. 3 and 4 indicate two conductor members or feeders connecting said mains,'said feeders being arranged in parallel, Each conductor or feeder is shown as provided at each end with a cut-out switch 5 by which it may be disconnected from the. system, and I have shown each switchas controlled or actuated by a trip coil 6 that is in a circuit 7 containing a bat-- tery '8. or other source of electrical energy. The two trip coils 6 at each end of the'condue-tors 3 and 4 are shown in the same circuit '7 so that when this circuit is energized, both trip [coils therein are energized and both,

conductors are thereby disconnected from said end of the system. The parallel feeders oi-conductors 3 and 4 play carry currents of different values for any one of the various reasons above suggested,tlmt is, the current in the conductor? may under normal working conditions'differ considerably from that in the conductor 4'. This current difference is commonly described as the differential current. My invention, as stated above, comprises means for disconnecting said conductors from the system, which means is nonoperative so long'as the ratio between thecurrent values in the conductors 3 and 4 is Within a predetermined limit, but which becomes operative whenever such' ratio exceeds such predetermined limit. -The conductors '3 and 4 are, therefore, permitted to carry currents of different values uninterruptedly so long as the ratio between the current values is. within a predetermined I amount, but when the ratio exceeds or goes beyondthis predetermined afnount, then the device becomes operative to disconnect the condl ictjorsfrom the system.

The circuit js-nornially open atthe contacts 9, and'means are cmployedtfor closing this circuit when the ratio'between the cur- "rent valifs carried by the'conductors 3 and- 00' 4; exceeds a predetermined 'limit,- which means is non-operative to close the circuit so lon as said ratio is within a predetermined limit. The device shown in Fig. lfor this urpos'e comprises'two elements, each. carrymg two windings, one element being relatively fixed and the other element being relatively movable. Each element is wound with two coils, the relative number of turns in the coils being chosen with regard to the percentage of unbalance it is desired to permit the parallel conductors to operate under. The two elements of the relay comprise the relativelyfixed element 10 and the relatively-movableelement 11, which is shown as pivotally mounted at 22. This fixed element 10 is wound with the two coils 12 and 13, and the relatively-movable element 11 is wound with the two coils 14 and 15.

The winding 12 on the element 10 and the winding l on the element 11 are connected in series in a circuit 16 which has thereinthe secondary 17 of a transformer, the primary 18 of which is in the conductor 3. Similarly, the winding 13 of the element 10 and the winding 15 on the element 11 are in series in a circuit 19.which has therein the secondary 20 of a'transformer, the pri- 'niary 21- of which/is in theconductor 4.

XVith' this arrangement, the current carried by the conductors 3 and 4 will induce cur- ,9 0

13 predominates over the winding 12, and 00.

the winding 14 predominates over the winding 15, and as aresnlt under normal-conditions the element 11 which is pivoted 8.15.22 will tend to move counter-clockwise.- i-This element 11 carries a-eontact 23 which is hormally held against a 'stop'24 b the'arrange..

ment above described, but which is adapted i to close the contacts 9 'when said element 'moves away fromthe s top. The arrangement of these windings is such that solong as the ratio between the current} values in'the con'ductors 3 and 4-;remains,within a'predetermined limit, the contact23 ,will be held against the'stop 24, but if abnormal c0ndi-,

tionsarise which result in aisuliicient in- I crease or decreasefin the current in one conductor relative to'tha't in the other tocanry,

the ratio between;- the currents-be odd-the predetermined j amount, the hereto ore predominating winding 'bf'bdieielement only ceases ed m na e ,flndr i 'ibompani n Y winding becomes piedominati-ve whereby the 'polarity of said elementzis. reversed, thus .causing'the .movable element 10 to move clockwise and close the circuit 7 at the contact-s 9. This results in operating the trip coils 6 and opening the feeders at 5.

As illustrating the operation it may he assumed that the two windings on each element are in a ratio of four to three, in whfch ciise'the conductors 3 and 4 would be per mittedjo. carry current values varyin from each other by the ratio three to four efore the relay has any tendency to operate. If,

5 however, the current in the conductor 4-,"fo'r instance, should increase relative to that in the conductor 3 so hat the ratio hetween the current values in the two conductors was greater than three to four, such increased current will cause the winding to predominate over the winding 14, thus reversing the polarity of the element 11 and causing the relay to operate." In case the relative increase in current should be in the conductor 3, then when the relative current winding 12 will be caused to predominate over the winding 13, thus reversing the polarity= of the'elementdo andcausing the relay tngoperate similarly. 1"

The de ice will, therefore, remain inactive .so long as the ratio between the current values in the,c'ondu ctors' 3- and 4 remains within the predetermined limit, regardless of the currents in the twov conductors vary to such an extent. that the ratio of saidalues exceeds theredefermined limit 'for. which the relay is esigned, then said relay becomes operative to cut the conductors from a the system.

IniFig. 2 I have shown tease: embodiprinc'iple, however. In this embodiment of the inventionthe relay for closing the 'cir cuit -T comprises the two cores 32 and 33 ectcd to the pivoted yoke 31 to which the contact 23 is rigidly secured. j The secondary of the-transformer in the con- J-ductor4 is connected to' a circuit 34 which has therein a winding'35 ior the core 32 and another winding 36 for the core 33.

gTh-seconday 17 of the transformer asso- 4 t e 37 having therein onewinding 38' for the ciatedfiwith conductor 3 is in a circuit core 32 and another winding 39 for thecore ,33. {l'lhe windings 35, .38 forthe core 32 are arranged .to augment each other under ings 39. and 36 for the core 33 are arranged 'to oppose each other under normal current conditions; lls a result the core 32 is sub ect to the, combined action of the coils '35 i5 gnd 38,IWhilo the core 33 is-acted upon by" jthe difference in effect between the windings. "-36 and-3,9. Said windings 36 and 39 are relatively fine windings, while the other wlndin are relatively coarse windings, and

4. The efi'ect of the windings of fluctuations in the current carried by said conductors, but as soonfas the relative values "ment of my invention (operating on the same normal current conditions, while the wind-.

ductors 3 and 4 varies beyond the predeter m ned amount, one of the windings 36, 39 Wlll predominate over the other sufiiciently to overcome the effect of the windings 35, 38

on the core 32, thus turning the yoke 31 and causing the contact 23 toclose the circuit 7, with the result that the conductors will be cut out from the circuit.

In Fig. 3 I have shown another embodiment of my invention which has a relay comprising a fiired and movable element 10 and 11, as shown in Fig. 1. In this embodiment, however, each element has a single winding thereon, the element 10 having a winding 42 in a circuit 43 includin the go I secondary 17 associated with the con uctor 3 and the element 11 havin a winding 44 thereon in a circuit 45 havm therein the secondary 20'associated with t econductor is to hold the'element 11 against the stop 40 under-normal conditions of current How in conductors. 3 and 4. This element 11 has .rigid therewith an arm' 46 which is con-' nected by alink 47 with the movable core ,48 in acoil. or solenoid having two oposed windings 1-49 and 50 thereon, one o the v windings" being in a'circuit 43 and the. other in'the circuit 45. These windinsf49and 50 are so designed that so long betweenthe current values in t core 48 is insuflicient to overcomethe action of the windings 42- a'nd 44. When, however, the ratio between thecurrent values in .the conductors 3 and -;4 exceeds the predetermined .ratio then the windings49 and 50 predominate dyer 'r assist theaction of the otherwindings, th1s v and closing the ci cuit 7 atthe contacts 9,-

thereby cutting the conductors from the an cuit. 5

In Fig. 4 I haveshown an embodiment of;

my invention similar to that shownjin Fig.1

2 in that 'the contact 23 for -closin the circuit.? is carried by a pivotdyo e 31 to;

'which is attached the two :cores 5 2 -and 53.'

The core 53 has a coarse wind ng. 54 thereon which is in a circuit '550 that ncludes bothh 'j of the secondaries 20 and 17 associated with the conductors 4 and-3, said winding beingplaced insaid circuit 'midway electricallyjbe,

tween thej sccondariesfl and 20 ,The core V the central portion of the winding 54'a1id one side of the circuit 550 at a point niiilwity elcctricully'between the secondaries l7 and 20. With this arrangement 4:2 and 44 35 as the ratio eeonductors 3 and 4 is within the predetermined limit, the resultant effect-of the windings on the turning the element 11' J indin 'fi thereon which is .the rat o.betweenethe fine and coarse windthe core 53 ill he subjectltghthe combined125 r ings' is chosen withrelatic'n to the prcduteraction t current induce'd by both transmined ratio between the current Values perforu *ile'thewindiif 55 will be sub- -mit te'd-to exist in the conductors 3 and 4. jKLiJ to -"5'; action of the ifierence of said 'If abnormal conditions arise by which the currents. The coil 54' will i predominate 65;.ratio betweenthe current values in the conunder normal conditionsand' thus holdthe herein shown as a core element 61 having contact 23 against the stop 40. Then the ratio between the currents carried by the conductors 3 and 4 varies to, such an extent that the fine winding 55, will predominate over the winding 54, then the contact 23 will be actuated to close. the circuit 7.

In Fi 5 I have shown another embodiment of my invention which is similar to that shown in Fig. 3 except that in the place of the difi'erential coil 49, of Fig. 3, I use a choke coil having two windings, one in each of the circuits 43 and 45. These wind ings are so constructed that if when the, currents in the conductors 3 and, 4 are in the same direction the ratio between the currents in said conductors increases'beyond the predetermined amount, then one of the windings will predominate over the other suiiiciently to reverse the current in the letter winding and thus reverse the polarity ofonc of the, elements of the relay. In case the. ratio between the currents in the conductors 3 and 4 increases beyond the predetel-mined amount, due to a reversal of current flow in one conductor relative to that in the other, then the polarity of one of the elements 10 and 11 is reversed without the assistance of the choke coil, which in such case, becomes negligible in its effect on the operation of the relay. The choke coil is the two windings 62 and 63 thereon, the winding ()2 being in the circuit 45 which includes the winding 44 of the relatively-movable element 11 ot' the relay, and the winding 63 of the choke coil being in the circuit- 43. which includes the winding 42 of the rein tivelwtixed element 10 of the relay, The two windings (32. 3 under unbalanced current conditions cooperate as a transformer and are arranged so. that each winding induces in the other winding a current opposed to thtit normally existing therein. With this construction it will be seen that if whenever the qturents in the conductors are in the same dimotion and the current in either of the conductors increases relative to that in the other to Such an extent as to carry the ratio between the currents outside the predetermined limit. then one of the coils 62, 63 will predominate over the other coil sufficiently to reverse the direction of current in the circuit of said other coil and thus reverse the polarity of one element of the relay. \Vhen reversal of polarity of one element of the relay occurs, due to either the cooperation of the choke coil or to the reversal of current in one of the conductors, relative to that in the other, the circuit 7 will be closed by the relay and the conductors will be disconnected from the system.

In Fig. somewhat similar to Fig. 4 except that the connections are such that the coarse wind 6 I have shown an apparatus 7 open, but if this ratio'increases beyond a certain amount,-the COll 55 'will predominate thus closing the circuit.

All of the above embodiments of my invention are illustrated as applied to a pair of parallel feeders onhr. My invention is also applicable where, more than two parallel feeders are employed, and in Fig. 7 I have illustrated such an embodiment of my invention. In this arranvement the relays for the various conductors or feeders are electrically connected with eachother and the cooperation of two relavs .is necessary "to close the tripp g circuit for the trip coil of anv conductor. In Fitz. 7 1 indicates the main and a, b, 0 indicate threeparallel feeders. A switch 5 is p'rovid'edfor' connecting each feeder to the main 1, each switch being controlledby a trip coil 6. A, B and'C indicate" the relays, these relays .being shown of the type illustrated in Fig.

1, thatis. each comprising a relatively-stationary element 10 and therelatively-movable element 11 pivotall mounted n22 and carrying the contact member 23.

Each stationary element 10' is. provided with two windings 120, 130, and each movable element is provided with two, windings 140, 150. The windings 130, 12 end'glso the windings'140, 150 are normally opposed to each .other'an d the: number ofturnS- ineach winding is chosen with relation to the percentage of mit between the current .in'eny conductor and that of any other conductor. The winding 120 of each relay is not onl'y connected in. series with the winding 140'ofthe same relay and thesecondary 170 oi the trans former in the adj acent conductor, but iselso. connected in series. withthef windings 130 and 150 of the next adjacent relay. The circuit 70 of. each trip coi1 .6 is provided with two pairs of-contacts, one pair 90 .being closed by the contact element 23. of one relay and the other air. contact 23 0f t e'next adjacent relay with which. the firstmeiuedrelay is electrically connected; It will-E; of course, be understood that the circuit connections w, m, y, E

with the 91 being closed by the ioo i 1,27e,ss1

' creases for any reason to such an extent thatthe ratio between said current and that in the other conductors exceeds the predetermined limit, then the relays B and C become operative thereby closing the contacts.

The relay B will close the trip coil circuit 70 for the conductor 6 at 90, and the relay C will close said circuit at 91, thus energizing the trip coil 6 and cutting the conductor 5 from the system. This operation disconnects the conductor 6 from the system.

In the embodiment of my invention shown in Fi 2, 4 and G'it will be noted that each re ay is influenced by both the sum and the difi'ercnce of the currents in two conductors and that the construction is such that the effect on the relay of the sum of the currents under normal working conditions redominates over the efi'ect thereon of t e difference between the currents,

so that the relay will normally be retained in its inoperative position. When, however, abnormal current conditions arise which produce. a difi'erence between the currents 1n said conductors which is greater than a predetermined percentage. of the current in parallel-connected conductors extending between two 'points in anelectrical transmission or distribution system, of relays for disconnecting said conductors from the system, and relay-controlling means which ,holds .the relays inoperative solong as the I ratio of the currentsin the conductors of any assoclated pair of conductors remains Withratio of the-currents carried in theconduc-v tors of said pair exceeds a predetermined conductor of said other conductor. I V 2. The combination with two parallelconnected conductors extending between a in a predetermined limit, but which renders 'saidirelaysoperative to disconnect said pair of conductors-from the system whenever the limit due to an increase'or a decrease or a reversal in direction of the current in either pair relative to that in the receiving and. distributing station, of a cutout at each end of each conductor, and operatingmeans'themfor which is held inoper ative so long as the ratio between the cur- "mains within a predetermined limit, but Which becomes operative-when said ratio exrent carried in said conductors remains 55 within a predetermined limit, but which becomes operative whenever the ratio oithe currents carried in the conductors exceeds a predetermined limit due to an increase or a dccease or reversal of direction of the current in one conductor relative to that in the ot ier.

3. The combination with a' plurality of; I

parallel-connected conductors extending tween two points in an" electrical transmission or distribution system, of rela s for disconnecting said conductors from t e system, and means connectin said relays to the system whereby each re ay is sub'ect to 80 r of the currents in two associated parallel the effect of both the sum and the di erence conductors and under normal working conditions will be held inoperative by the preponderance of the effect of the sum of the currents over the efiect of the difference, but will become operative to disconnect the conductors from the system whenever the cur:

rent in one of said conductors increases; de-

creases or reverses indirection relative to that in the other conductor thereb' to roduce a current difierence in sai con uctors which exceeds a predetermined percen tage of thecurrent in either conductor.

I 4. In a system of electrical transmission. or distribution of that type having a plurality of parallel-connected conductors grouped iii-feeding sections and subject to power flow in either direction, the combination with disconnecting devices for disconnecting each of the conductors from the system, of means to cause the disconnecting devices for any conductor to become operative to disconnect said conductor-- from the system only when the ratio between the 1":- 105,,

value of the current therein" andithevalue of the current inan associated conductor ex ceedsa predetermined limit dueto, a fault involving the first-named conductor.

5; In a systemsnowmen transmission or distribution of that having a pluralityof" arallel-connected f conductors grouped in. eedingsections and subject to power flow ineither direction, the combine tion withdisc9nnectingdevices for discontthe conductors firom the sys- V k or 'actuatingthe ingdeviceswhichmeans are inoperative so long as the ,ratio between the valueof the current in any conductorand the value of' the current in-an associated conductor re? ceeds said limit due toa fault involving either of saidiconductors, g

' '6. In a system of electrical transmission or distribution of that type having a plurality of. parallel-connected conductors grouped 1n feeding sections and subject foo power'flow in either direction, the combination with disconnecting devices for disc0nnectin each.0f the conductors from the tern, 0% 5 vice for any conductor to operate there y to disconnect said conductor from the system Whenever the current therein has a value means to cause the disconnectin degreater than the maximum or smaller than the minimum value permitted by a predetermined ratio-0f maximum to minimum 10 current value in the parallel conductors.

In testimony whereof, I have signed my name to this specification.

WILLIAM H. COLE. 

